Elephants remember ... and get cancer less often

For a long time, there was a current myth that sharks do not get tumors, so for a long time they were fashionable (and still are) preparations based on shark cartilage that miraculously and pseudo-scientifically "cure cancer".

However, today I will not talk about it. Today I’m going to write about how elephants don’t get cancer quite often.
Namely, science today believes that elephants and large animals rarely get cancer. So - science does not claim that elephants do not get cancer, but that it happens very, very rarely. About 4.8% of deaths in elephants are caused by cancer, compared to 11-25%in humans. Small animals, such as mice, get cancer much more often.

This paradox is called Peto's paradox, after Richard Peto, a professor of medical statistics who described this unusual situation in the 1970s - that large organisms, which have more cells, have a lower incidence of cancer. that there is no correlation between the size of the organism and the incidence of cancer ..

One adult elephant can weigh 4,800 kg, which means that one such elephant has 100x more cells than you. More cells - more chances of some damage to the DNA that would lead to the formation of malignant cells.
In a paper published recently in the Journal of the American Medical Association (here you can find a preprint of a paper on this, and here a paper I'm talking about, which for some reason I can't open), scientists described the mechanisms of this strange trait of elephants. Namely,scientists have found that elephants have as many as 20 copies of the TP53 gene. This gene encodes the p53 protein, one of the most important proteins that protects DNA from damage by not allowing cells to divide until the error is corrected. If a cell does not repair the DNA damage, p53 forces that cell to "cell suicide." Thus,p53 acts as a tumor suppressor. Man has only one copy of this gene.Dr. Joshua Shiffman, of the University of Utah’s Huntsman Cancer Institute in Salt Lake City, has teamed up with Barnum & Bailey Circus (which donated $ 250,000 for this research) and their team of veterinarians to conduct this research.This scientific paper suggests that the existence of so many copies of TP53 is due to duplications from some million years ago, which have accumulated over time in the genome. Thus, a mutation occurred that in this case was beneficial to the organism.
Another study showed that an elephant cell exposed to ionizing radiation, destroys itself twice as fast as a human cell that has both alleles for TP53 functional (alleles are gene variations, in the genome and we have 2-one from the father, the other from the mother).

Scientists hope that understanding the cell protection mechanism that exists in elephants could help create a drug that mimics this mechanism. It took evolution 55 million years for elephants to do that.